1. Field of the Invention
The present invention relates to an image output system which is suitably provided in an image processing system of, for example, a video camera apparatus, camera apparatus, computer system or the like.
The present invention relates to a contour compensation system which is suitably provided in an image processing system of, for example, a video camera apparatus, camera apparatus, computer system or the like and, more particularly, to a contour compensation system which is adapted to perform contour compensation processing with respect to an image data or image pickup data portion having a frequency band that corresponds to the zoom magnification of an electronic zoom of the image data or image pickup data.
The present invention relates to an electronic zoom circuit which enlarges electronically in, for example, a video camera apparatus a digital video signal input from the camera part, or a digital video signal reproduced from the video part.
2. Description of the Related Art
Presently, there is known a digital video camera apparatus which digitalizes an image pickup signal obtained by imaging a desired object and records it in a video cassette tape.
This digital video camera apparatus has inputted thereto an image pickup light by a CCD image sensor and thereby forms an analog image pickup signal that corresponds to the amount of this image pickup light. After having been amplified with a suitable gain and digitalized, this image pickup signal is subjected to gamma correction processing and then supplied to a contour compensation circuit. The contour compensation circuit forms contour compensation data having a prescribed stressed frequency of the image pickup data by the use of a contour compensation coefficient that is made to be a fixed value. It adds up this contour compensation data and the original image pickup data and thereby performs contour compensation processing on this image pickup data and supplies the resulting data to the electronic zoom circuit.
The electronic zoom circuit performs line interpolation processing or the like on the image pickup data having the contour compensation processing performed thereon, so that the image pickup data may have a magnification designated by the user, thereby electronically enlarging the imaged object and outputting the same. The image pickup data having had this electronic zoom processing performed thereon is stored once in a frame memory and is read out in units of a field by the image output circuit in correspondence with a record rate. And, prescribed video process processing is performed thereon and the resulting image pickup data is recorded in a video cassette tape.
However, the conventional digital video camera apparatus is so arranged that the image output circuit may read out the image data stored once in the frame memory as it is in a form divided in units of a field for recording thereof. Therefore, in the stage output from the frame memory, it cannot process the image pickup data whatsoever and so there was the problem that the image quality could not be improved. With a view to the fact that the characteristics of the image pickup data differ for each image pickup conditions, image pickup mode, or the like, there have hitherto been wanted developments of a digital video camera apparatus which can vary the characteristics of the output (recorded) image pickup data in correspondence with these conditions, mode or the like.
On the other hand, also, in the conventional digital video camera apparatus, the contour compensation coefficient of the contour compensation circuit is made to be a fixed value. As a result, the frequency band that is stressed by the contour compensation processing is limited (fixed). Therefore, there was the problem that when high-magnification electronic zoom processing was performed with the use of the electronic zoom circuit, the return noises increased with the result that the frequency characteristic and S/N ratio deteriorated, causing deterioration of the quality of the displayed image.
It is to be noted that while Japanese Patent Application Laid-Open Publication No. 5-122577 discloses a video camera apparatus that makes a variable control of the contour compensation coefficient value in correspondence with the enlargement factor of the electronic zoom and that thereby prevents the deterioration of the resolution, such a conventional technique is one which makes a variable control of the xe2x80x9ccorrection levelxe2x80x9d by changing the contour compensation coefficient value equally. Namely, this technique realizes the contour compensation processing by making a vertical control of the level as a whole of the image pickup data. For this reason, it is difficult to perform excellent contour compensation processing and said technique does not go up to the stage of solving the above-described problems.
Meanwhile, in the electronic zoom circuit, it is possible to perform an electronic zoom control of not only a video signal input from the solid image pickup element but also a video signal reproduced from a digital video tape.
FIG. 1 is a block diagram illustrating an electronic zoom circuit that performs processing of a luminance signal by a spline interpolation system and that of a color difference signal by a linear interpolation system. To an input terminal In there is input a 12-bit video signal taken from a solid image pickup element or a 12-bit video signal reproduced from a digital video tape. Of this 12-bit input signal, an upper order 8-bit component signal is a luminance signal and a lower order 4-bit component signal is a color difference signal.
In FIG. 1, reference symbols L1, L2, L3 and L4 represent line memories in each of which there is stored a 1-line video signal and each of which delays this signal in units of one horizontal scanning time-period and sequentially outputs the resulting delayed signal. A reference symbol 60 represents a luminance signal/color difference signal separation circuit to which there are input the 1-line video signals from the line memories L1 to L4, each signal corresponding to one line and which separates the upper 8-bit luminance signal and lower 4-bit color difference signal and thereby outputs these separated signals.
Also, a reference symbol 61 represents a vertical spline interpolation circuit that performs vertical spline interpolation processing according to the 4-line luminance signals output from the luminance signal/color difference signal separation circuit 60. A reference symbol 62 represents a vertical linear interpolation circuit that performs vertical linear interpolation processing according to the 2-line color difference signals output from the luminance signal/color difference signal separation circuit 60.
Also, a reference symbol 63 represents a horizontal spline interpolation circuit that horizontally enlarges the luminance signal vertically enlargement processed by the vertical spline interpolation circuit 61. A reference symbol 64 represents a horizontal linear interpolation circuit that horizontally enlarges the color difference signal vertically enlargement processed by the vertical linear interpolation circuit 62.
With the above-described construction, the 12-bit video signal that is input to the input terminal In is subjected to selection of the output data or to adjustment of the timing by the line memories L1 to L4, whereby the resulting signals are input as the successive 4-line video signals to the luminance signal/color difference signal separation circuit 60.
Thereafter, 8-bit data of the luminance signal and 4-bit data of the color difference signal are processed, each, by the vertical and horizontal interpolation circuits. Here, while the color difference signal is output as 4-bit data, this signal is converted to an 8-bit data signal by a color difference 8-bit signal converter circuit not illustrated and, after passing through a video process executing system, is recorded into a digital video tape.
It is to be noted that in a case where reproducing a video signal recorded in the digital video tape and performing zoom processing on the reproduced video signal, also, since the reproduced video signal is composed of an 8-bit luminance signal and a 4-bit color difference signal, it is possible to perform zoom processing thereon also similarly by the electronic zoom circuit.
Meanwhile, there has in recent years been developed an all-pixel readout system solid image pickup element which can output 1-frame pixel data in units of a 1-field period, that has been taken thereinto in units of a 1-field period, in the form wherein this 1-frame pixel data is divided into even-line data, (a) channel data, and odd-line data, (b) channel data, such all-pixel readout system solid image pickup element being in the course of being adopted in the video camera apparatuses as well. However, in the electronic zoom circuit, it is not possible to perform zoom processing according to both of the even-line data and odd-line data that are output from the all-pixel readout system solid image pickup element.
Accordingly, it results that zoom processing is performed according to either one of the even-line data or odd-line data. As a result, it was only possible to obtain a zoomed image of the same quality as that which was attainable when zoom processing was performed using a conventional solid image pickup element which output even-line data or odd-line data in units of a 1-field.
The present invention has been made in view of the above-described problems and has an object to provide an image output apparatus which can vary the characteristic of image data output according to the image pickup conditions, image pickup mode, or the like, as well as an image pickup apparatus including the image output apparatus.
Also, another object of the present invention is to provide a contour compensation system which even in a case where performing, for example, high-magnification electronic zoom processing by the use of an electronic zoom circuit makes it possible to mitigate the return noises resulting from such electronic zoom processing or the like and thereby prevent the deterioration of the frequency characteristic and S/N ratio of the image and thereby enhance the quality of the displayed image, as well as an image pickup apparatus including the contour compensation system.
Further, still another object of the present invention is to provide an electronic zoom circuit which can perform zoom processing according to both of even-line data and odd-line data output from an all-pixel readout system solid image pickup element.
To attain the above object, there is provided an image output apparatus, comprising: image output means having an output mode in which first and second image data forming one image data are addition processed in a ratio of xcex1:xcex2 other than the ratio therebetween whose value is 1 to thereby form first output image data whose amount is the same as that of the first or second image data, the first output image data being output therefrom; and the first and second image data are addition processed in an inverted ratio of xcex2:xcex1 from the ratio therebetween that has been used when addition processing has been performed in order to form the first output image data to thereby form second output image data whose amount is the same as that of the first or second image data, the second output image data being output therefrom.
To attain the above object, there is provided an image output method comprising the steps of addition processing first and second image data forming one image data in a ratio of xcex1:xcex2 other than the ratio therebetween whose value is 1 to thereby form first output image data whose amount is the same as that of the first or second image data and output the same, and addition processing the first and second image data in an inverted ratio of xcex2:xcex1 from the ratio therebetween that has been used when addition processing has been performed in order to form the first output image data to thereby form second output image data whose amount is the same as that of the first or second image data and output the same.
To attain the above object, the present invention provides an image pickup apparatus, comprising: image pickup means for imaging an object and outputting image pickup data; and image output means having an output mode in which first and second image data supplied from the image pickup means as image data forming one image data by two image data are addition processed in a ratio of xcex1:xcex2 other than the ratio therebetween whose value is 1 to thereby form first output image data whose amount is the same as that of the first or second image data, the first output image data being output therefrom; and the first and second image data are addition processed in an inverted ratio of xcex2:xcex1 from the ratio therebetween that has been used when addition processing has been performed in order to form the first output image data to thereby form second output image data whose amount is the same as that of the first or second image data, the second output image data being output therefrom.
To attain the above object, there is provided an image pickup method, comprising: the step of imaging an object by image pickup means and thereby outputting first and second image data from the image pickup means as image data forming one image data by the first and second image data; and the step of addition processing the first and second image data obtained by execution of the preceding step in a ratio of xcex1:xcex2 other than the ratio therebetween whose value is 1 to thereby form first output image data whose amount is the same as that of the first or second image data and output the same, and addition processing the first and second image data in an inverted ratio of xcex2:xcex1 from the ratio therebetween that has been used when addition processing has been performed in order to form the first output image data to thereby form second output image data whose amount is the same as that of the first or second image data and output the same.
To attain the above object, there is provided a storage medium having Stored therein an image output program comprising the steps of addition processing first and second image data forming one image data in a ratio of xcex1:xcex2 other than the ratio therebetween whose value is 1 to thereby form first output image data whose amount is the same as that of the first or second image data and output the same, and addition processing the first and second image data in an inverted ratio of xcex2:xcex1 from the ratio therebetween that has been used when addition processing has been performed in order to form the first output image data to thereby form second output image data whose amount is the same as that of the first or second image data and output the same.
The image output system according to the present invention is so arranged that the system can perform addition processing on the respective image data in an optimum ratio in correspondence with the cases by having the above-described characteristic respective means (steps) and can improve the quality of the image through the enhancement of the frequency characteristic and through the enhancement of the S/N ratio.
It is to be noted that, assuming that the unit amount of, for example, each of the respective image data be xe2x80x9c0.5xe2x80x9d, the wording of xe2x80x9cthe ratio of xcex1:xcex2 whose value is 1xe2x80x9d means that the ratio between the image data is xe2x80x9c0.5:0.5xe2x80x9d. The wording of xe2x80x9cthe ratio of xcex1:xcex2 whose value is other than 1xe2x80x9d means that the ratio between the image data is xe2x80x9c0.25:0.75xe2x80x9d; xe2x80x9c0.75:0.25xe2x80x9d, xe2x80x9c0.45:0.55xe2x80x9d or the like. Incidentally, it is added that these values are only illustrative with an aim to have a better understanding of the present invention.
On the other hand, while the image pickup apparatus associated with the contour compensation of the present invention has the respective characteristic means capable of solving the above-described problems as seen in the following description, the difference between the conventional technique and the present invention will now be made clear prior to the description thereof.
The video camera apparatus that is disclosed in Japanese Patent Application Laid-Open Publication No. 5-122577 previously referred to is so arranged as to change equally all the contour compensation coefficients and thereby make a variable control of the xe2x80x9ccorrection levelxe2x80x9d. In other words, it realizes contour compensation processing through a vertical control of the level as a whole of the image pickup data.
In contrast to this, the present invention is one which has been derived from a completely novel and advanced technical idea and is so arranged as to perform contour compensation processing on the xe2x80x9cfrequency bandxe2x80x9d of the image pickup data in correspondence with the zoom magnification of the electronic zoom, namely executes partial contour compensation process of the image pickup data.
Accordingly, to attain the above object, there is provided a contour compensation arrangement, comprising: electronic zoom means for electrically enlarging an image formed by image data; and contour compensation means for performing contour compensation processing with respect to an image data portion in a frequency band corresponding to a zoom magnification of the electronic zoom means.
To attain the above object, there is provided a contour compensation method, comprising the step of performing contour compensation processing with respect to an image data portion in a frequency band corresponding to a zoom magnification of an electronic zoom for electrically enlarging an image formed by image data.
To attain the above object, there is provided an image pickup apparatus, comprising: image pickup means for receiving an imaging light of an object and outputting image pickup data corresponding to the received imaging light; optical zoom means for performing optical enlargement processing on an imaged object image according to the imaging light of the object received by the image pickup means; and contour compensation means for performing contour compensation processing with respect to an image pickup data portion in a frequency band corresponding to a zoom magnification of the optical zoom means.
To attain the above object, there is provided an image pickup apparatus, comprising: image pickup means for receiving an imaging light of an object and outputting image pickup data corresponding to the received imaging light; electronic zoom means for performing electric enlargement processing on an imaged object image according to the image pickup data from the image pickup means; and contour compensation means for performing contour compensation processing with respect to an image pickup data portion in a frequency band corresponding to a zoom magnification of the electronic zoom means.
To attain the above object, there is provided an image pickup method, comprising: the step of imaging an object by image pickup means; the step of performing optical enlargement processing on an imaged object image according to an imaging light of an object received by the image pickup means; and the step of performing contour compensation processing with respect to an image pickup data portion in a frequency band corresponding to a zoom magnification of the enlargement processing step.
To attain the above object, there is provided an image pickup method, comprising: the step of imaging an object by image pickup means; the step of performing electric enlargement processing on an imaged object image according to an image pickup data from the image pickup means; and the step of performing contour compensation processing with respect to an image pickup data portion in a frequency band corresponding to a zoom magnification of the enlargement processing step.
To attain the above object, there is provided a storage medium having stored therein a contour compensation processing program that comprises: the step of performing contour compensation processing with respect to an image pickup data portion in a frequency band corresponding to a zoom magnification of an optical zoom.
To attain the above object, there is provided a storage medium having stored therein a contour compensation processing program that comprises: the step of performing contour compensation processing with respect to an image pickup data portion in a frequency band corresponding to a zoom magnification of an electronic zoom.
The contour compensation system according to the present invention realizes optimum contour compensation processing corresponding to the zoom magnification or the like and enhances the quality of the image by having the above-described characteristic respective means (steps).
To attain the above object, there is provided an electronic zoom circuit, comprising: first and second input means for having inputted thereto respectively first and second digital video data signals that are produced from first and second image data signals that form 1-frame image data that is output from a solid image pickup element in units of 1 field; selection/separation/output means for having inputted thereto a first line data signal constituted by a plurality of horizontal scanning line data signals contained in the first video data signal and a second line video data signal contained in the second video data signal and constituted by a plurality of horizontal scanning line data signals vertically adjacent to a plurality of the horizontal scanning line data signals of the first line data signal, selecting a plurality of the vertically adjacent horizontal scanning line data signals of the first and second line data signals, separating a plurality of the selected horizontal scanning line data signals into luminance data signal and color difference data signal, and outputting the luminance data signal and color difference data signal; and pixel interpolation means for performing vertical and horizontal zoom processings according to the luminance data signal and color difference data signal output from the selection/separation/output means.
To attain the above object, there is provided an electronic zoom circuit, comprising: input means for having inputted thereto a digital video data signal reproduced from a storage medium; selection/separation/output means for having inputted thereto a line data signal constituted by a plurality of horizontal scanning line data signals contained in the video data signal, selecting a plurality of vertically adjacent horizontal scanning line data signals of the line data signals, separating a plurality of the selected horizontal scanning line data signals into luminance data signal and color difference data signal, and outputs the luminance data signal and color difference data signal; and
pixel interpolation means for performing vertical and horizontal zoom processings according to the luminance data signal and color difference data signal output from the selection/separation/output means.
The nature, principle and utility of the invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings.